Borescope Inspection of the Low Pressure Turbine (LPT) Shroud Segments [CFML]

TASK 72-00-00-290-823-A
Borescope Inspection of the Low Pressure Turbine (LPT) Shroud Segments

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

ZONE: 400

1. Reason for the Job
This procedure gives the criteria for the borescope inspection of the Low Pressure Turbine (LPT) stage 1 to 6 shroud segments.

NOTE: You can use equivalent alternatives for standard tools, equipment and consumable materials.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M(3 FT)
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 55 and 50 lbf.in (0.62 and 0.57 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2619)	Never Seez-Pure Nickel, Special

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL, 462AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-803-A	Closing of the Fan Cowl Doors
TASK 72-00-00-290-812-A	Engine Borescope Examination Preparation
TASK 78-30-00-040-809-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-809-A	Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
TASK 78-36-00-410-806-A	Closing of the Thrust Reverser Cowl Doors
Borescope Inspection of the Low Pressure Turbine (LPT) Shrouds
Borescope Inspection of the Low Pressure Turbine (LPT) Stage 1 to 6 Shroud Segments
Honeycomb Inspection for Stage 5 and 6 Shroud Segments
Borescope Inspection of the Low Pressure Turbine (LPT) Stage 1 to 6 Shroud Segments Forward Plate

3. Job Set-up
Subtask 72-00-00-941-250-A

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put a WARNING NOTICE(S) in position to tell persons not to operate:

The ENG/MODE selector switch
The ENG/MASTER 1(2) control switch.

(2) On the ENG section of maintenance panel 50VU:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).

Subtask 72-00-00-010-341-A

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 72-00-00-040-164-A

C. Deactivation of the Thrust Reverser System for Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for ground maintenance (Ref. AMM TASK 78-30-00-040-809).

Subtask 72-00-00-010-342-A

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR.

4. Procedure
Subtask 72-00-00-010-354-A

A. Removal of the Borescope Plugs
(1) Remove the borescope plugs (Ref. AMM TASK 72-00-00-290-812).

Subtask 72-00-00-480-090-A

B. Assemble the Borescope Inspection Tools
(1) Assemble the borescope inspection tools (Ref. AMM TASK 72-00-00-290-812).

Subtask 72-00-00-290-145-A

C. Borescope Inspection of the Low Pressure Turbine (LPT) Stage 1 to 6 Shroud Segments:

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Borescope inspection of shroud segments Borescope Inspection of the Low Pressure Turbine (LPT) Stage 1 to 6 Shroud Segments
A.Distortion	No limit if the shroud segment does not extend into the air stream.
B.Wear, unbounded cells	No limit
2.Visual inspection of honeycomb Honeycomb Inspection for Stage 5 and 6 Shroud Segments
A. Metal deposit	LPT stage 5 and 6 shrouds segments: Any amount if no loss of cutter teeth on the front of the blade NOTE: The inspection of cutter teeth should be realized face to cutter teeth to see the radial gap between two blades.
3.Borescope inspection of shroud segments Borescope Inspection of the Low Pressure Turbine (LPT) Stage 1 to 6 Shroud Segments Forward Plate
A. Circumferential cracks (type X*) along the border of the brazing joint in the forward plate Zone A	Cracks on each end not more than 0.5 in. (12.7 mm) long NOTE: Type X*: Crack starting at one extremity of the brazing joint and propagating along the border of this brazing joint
B. Cracks initiating in the top-radius (type Y**) of the forward plate Zone B	Cracks on each end with a cumulative length* under 0.5 in. (12.7 mm) long NOTE: Type Y: Crack starting at one extremity of the top-radius of the forward plate Cumulative length***: Length of the line segment connecting the starting point of the crack at the end of the plate to the point of arrival of the last parallel crack
C. Simultaneous cracks type X and type Y	Not serviceable
D. Broken/Missing material in the forward plate	Not serviceable

Subtask 72-00-00-080-081-A

D. Removal of the Borescope
(1) Remove the borescope (Ref. AMM TASK 72-00-00-290-812).

Subtask 72-00-00-410-306-A

E. Installation of the Borescope Plugs

CAUTION: WHEN YOU INSTALL THE BORESCOPE PLUGS, MAKE SURE THAT:

THE LOCKING FEATURE IS IN ONE OF THE TWO GROOVES ON THE BORESCOPE BOSS, AND
THERE IS NO GAP BETWEEN THE BORESCOPE BOSS AND PLUGS IN THE END.

IF YOU DO NOT OBEY THESE CONDITIONS, THE BORESCOPE PLUGS WILL NOT BE CORRECTLY INSTALLED.

(1) Apply CP2619Never Seez-Pure Nickel, Special to the threads of the borescope plugs and install on the LPT case.
(2) TORQUE plugs to between 55 and 50 lbf.in (0.62 and 0.57 m.daN )

Borescope Inspection of the Low Pressure Turbine (LPT) Shrouds

5. Close-up
Subtask 72-00-00-410-297-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-410-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR.

Subtask 72-00-00-440-156-A

B. Do the reactivation of the thrust reverser system after ground maintenance (Ref. AMM TASK 78-30-00-440-809).

Subtask 72-00-00-410-298-A

C. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:51:03 UTC